An angiography system of this type is known for instance from U.S. Pat. No. 7,500,784 B2 which is explained with the aid of FIG. 1.
FIG. 1 shows a monoplanar x-ray system shown as an example having a C-arm 2 held by a stand 1 in the form of a six-axle industrial or articulated arm robot, to the ends of which an x-ray radiation source, for instance an x-ray emitter 3 having x-ray rubes and a collimator, and an x-ray image detector 4 as an image recording unit are attached.
By means of the articulated arm robot known for instance from U.S. Pat. No. 7,500,784 B2, which preferably comprises six axes of rotation and thus six degrees of freedom, the C-arm 2 can be spatially adjusted in any way, for instance by being rotated about a center of rotation between the x-ray emitter 3 and the x-ray image detector 4. The inventive angiographic x-ray system 1 to 4 can in particular be rotated about centers of rotation and axes of rotation in the C-arm plane of the x-ray image detector 4, preferably about the center point of the x-ray image detector 4 and about the axes of rotation which intersect the center point of the x-ray image detector 4.
The known articulated arm robot comprises a base frame, which is fixedly mounted for instance on a floor. A carousel is rotatably fastened thereon about a first axis of rotation. A robot rocker is pivotably attached to the carousel about a second axis of rotation, to which a robot arm is rotatably fastened about a third axis of rotation. A robot hand is rotatably attached to the end of the robot arm about a fourth axis of rotation. The robot hand comprises a fastening element for the C-arm 2, which can be pivoted about a fifth axis of rotation and can be rotated about a sixth axis of rotation which proceeds at right angles thereto.
The realization of the x-ray diagnostics facility is not dependent on the industrial robot. Conventional C-arm devices can also be used.
The x-ray image detector 4 may be a rectangular or square, flat semi-conductor detector, which is preferably created from amorphous silicon (a-Si). Integrated and possibly counting CMOS detectors can however also be used.
A patient 6 to be examined as the examination object is located in the beam path of the x-ray emitter 3 on a couch plate 5 of a patient support couch. A system control unit 7 with an imaging system 8 is connected to the x-ray diagnostics facility, said imaging system receiving and processing the image signals of the x-ray image detector 4 (control elements are not shown for instance). The x-ray images can then be observed on displays of a monitor 9. A known collision calculator 10 is further provided in the system control unit 7, the function of which is described again in more detail.
Instead of the x-ray system shown by way of example in FIG. 1 having the supporting stand 1 in the fond of the six-axle industrial or articulated arm robot, as shown in simplified form in FIG. 2, the angiographic x-ray system can also comprise a normal ceiling or floor-mounted retaining bracket for the C-arm 2.
Instead of the C-arm 2 shown by way of example, the angiographic x-ray system can also comprise separate ceiling and/or floor-mounted retaining brackets for the x-ray emitter 3 and x-ray image detector 4, which are fixedly electronically coupled for instance.
By means of the articulated arm robot known from the afore-cited U.S. Pat. No. 7,500,784, B2, rotation angiographs, so-called DynaCTs, can be created in order to generate 3D image recordings of an aneurysm for instance.
Angiography systems of this type are used in the field of fluoroscopy-controlled, interventional repairs of abdominal aortic aneurysms.
An abdominal aortic aneurysm (AAA) is an aneurysm on the abdominal aorta. This is treated by inserting a stent graft. Guide wires and catheters are introduced into the aorta by way of the two strips, by way of which one or several stent grafts, otherwise known as composite stent-graft devices, are introduced (see FIG. 3), such as are shown for instance in Cardiology today, January 2011, page 36. The aim when inserting these stent grafts is to position the “landing zone” of the vascular prosthesis as far as possible in the healthy vascular wall, but in the process not to cover any important vessel outlets. The outlets of the renal arteries, the superior mesenteric artery (arteria mesenterica superior), the truncus coeliacus, and the internal pelvic arteries (arteria iliaca interna) are to be kept free. One sensitive point is the disposal of the “main stent” in the aorta, whereby the said vessel outlets are not permitted to be closed. With complex stents which include the leg arteries, the final stent must sometimes be composed of “partial stents” (for instance an aortic stent to which stents for leg arteries are attached).
The so-called “roadmapping” technology is frequently used for the precise positioning of the stents, such as is described again by way of example for instance with the aid of FIGS. 4 to 9. The idea here is provide the physician with a type of “map” to navigate the instrument by continuously displaying the vessels. A mask image is herewith initially generated by administering contrast agent. The subsequently recorded fluoroscopy live images are now captured without contrast agent, nevertheless with an introduced instrument. If the mask image is deduced from the live images, the roadmap images are obtained, on which the anatomical background was “subtracted” and the vessels appear to be light-colored and the introduced instrument appears to be dark. The problem is that a new mask image has to be created for each new angulation.
In order, for monitoring purposes, not to have to inject contrast agent for a constant vessel representation during the complex stent positioning, a reference image can also be correctly anatomically overlaid which shows the vessels, in the case of the aorta and the outgoing vessels. This reference image may either be a 2D angiography (DSA—digital subtraction angiography) or, more expediently, a previously captured 3D image data record, for instance a CT angiography, of the aneurysm. These show more details and can be overlaid at any angulation of the C-arm (see FIGS. 4 to 9). Occasionally such a reference volume or image is also presegmented (see FIGS. 10 and 11).
This representation may however be unfamiliar to the physician. Furthermore, the overlaid reference image may possibly cover important details of the fluoroscopy image.
In summary, common knowledge is:                The manual or automatic segmentation of AAAs and the corresponding calculation of centerlines,        The (flexible) 2D/3D or 3D/3D registration, for instance of 2D and 3D angiographs,        The roadmap technology and        The adaptive 2D reference overlay, such as is described for instance in DE 10 2008 023 918 A1.        